[NLRS] [Mw] Boradwall Waveguide slots for antennas

[Dr. Gerald N. Johnson]

And for the convenience of cutting with a vertical mill.

73, Jerry, K0CQ

On 12/3/2015 4:05 PM, KENT BRITAIN wrote:
> The round ends are usually for high power applications.  WA5VJB
>
> ------------------------------------------------------------------------
> *From:* Dr. Gerald N. Johnson <geraldj at netins.net>
> *To:* Microwave list <microwave at lists.eclectechs.com>; NLRS Reflector
> <NLRS at mailman.qth.net>
> *Sent:* Thursday, December 3, 2015 3:55 PM
> *Subject:* [Mw] Boradwall Waveguide slots for antennas
>
> I know there has been some mention in references I have about round ends
> vs square ended slots, though most of the computation appear to be based
> on square ends to the slots and no thickness to the waveguide walls. Is
> there any literature showing a difference between the resonances and
> radiation of round vs square ended slots?
>
> Then is there any that allows for the slot in the inside of the guide
> being a different length than on the outside, as it would naturally be
> from cutting the slots with a metal circular saw blade? Or does all the
> literature presume all slots will be squared up by hand after the
> milling operations. With copper not a fun material to cut slots in with
> an end mill because its so gummy and grabby, I'm thinking cutting with a
> fine toothed saw blade would make much smoother slot walls and destroy
> way fewer cutting tools. Filing isn't much fun either with a file small
> enough to fit in a 10 GHz slot. The stroke can't be very long and the
> file has to be thin and weak. I have a large supply of 3" and 4"
> diameter metal saw blades that I can use, if the slot resonance and
> radiation aren't messed up by sloping ends on the slots. I also have
> collected a few 3/4" and 1" diameter but those won't get the ends
> perfectly perpendicular to the surface and have very coarse teeth
> compared to the bigger ones.
>
> 73, Jerry, K0CQ
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